The present invention relates to a disk drive unit in which a cartridge stored with a disk-shaped magnetic record medium, such as a floppy disk, is received, a magnetic recording head is brought into contact with the magnetic record medium as the magnetic record medium is rotated, whereby data are recorded in the magnetic record medium and reproduced from the magnetic record medium.
A disk drive unit for a floppy disk is designed so that a shutter of the floppy disk (disk cartridge) opens to expose a part of a magnetic record medium therein when the floppy disk is inserted and positioned at a loaded position. An upper magnetic head and a lower magnetic head come into contact with the upper and lower surfaces, respectively, of the exposed disk, thereby recording data in the disk and reproducing data from the disk. When the disk drive unit is not loaded with the floppy disk, the upper magnetic head is situated at a distance from the lower magnetic head.
Many of upper and lower magnetic heads are formed using ceramic materials. If the disk drive unit is subjected to vibration or shock when it is not loaded with any disk cartridge, the upper magnetic head and the lower magnetic head come heavily into contact with each other, whereupon the heads are damaged.
Accordingly, a mechanism (magnetic head lift mechanism) designed in the following manner is used. When the disk cartridge is not inserted in the disk drive unit, that is, when the upper magnetic head is separated from the lower magnetic head, the mechanism fixes this separated state to prevent the upper magnetic head and the lower magnetic head from running against each other if they are subjected to vibration or shock. When the floppy disk is inserted, on the other hand, the mechanism releases the upper magnetic head and the lower magnetic head from the fixedly separated state.
Since magnetic head lift mechanisms having so far been proposed are complicated in construction, they cannot be easily stored in a narrow space in the disk drive unit. Therefore, they cannot satisfactorily meet the demand for thinner, smaller disk drive units without ruining appropriate strength against shock.
In a magnetic head lift mechanism described in Japanese Patent Application Laid-Open No. 9-17137, as shown in FIGS. 37A and 37B, a lifter 351 for supporting an upper magnetic head 321 off a lower magnetic head is provided on the upper surface of a cartridge holder 303 (carrier) that carries a disk cartridge 309 thereon, the lifter 351 being in engagement with an upper magnetic head support member 341 which is fitted with the upper magnetic head 321. When the cartridge holder 303 moves up and down as the cartridge 309 is loaded and unloaded, the lifter 351 rocks so that its distal end moves up and down.
This lift mechanism is provided with shock preventing means that serves to prevent the lifter 351 from descending if it is subjected to vibration or shock. One of the shock preventing means is an extending portion 322 of a shutter lever 312 which is inserted below the lifter 351, and another is a holder guard 307 that serves to prevent the cartridge holder 303, which is fitted with the shutter lever 312 and the lifter 351, from sinking, as shown in FIGS. 38A and 38B. The holder guard 307 is formed of a springy member. When the cartridge 309 is inserted into a disk drive unit, the holder guard 307 is pushed to be displaced by the cartridge 309, thereby allowing the cartridge holder 303 to descend. When the disk drive unit is not loaded with the cartridge 309, on the other hand, the holder guard 307 is returned to its original position by its elasticity, and its receiving portion 378 prevents the cartridge holder 303 from descending.
According to the magnetic head lift mechanism described above, the lifter 351 is provided on the upper surface of the cartridge holder 303, and the lifter 351 is rocked up and down when the cartridge holder 303 moves up and down as the cartridge 309 is loaded and unloaded, so that there is no need of any special drive unit for rocking the lifter 351. However, the range of vertical movement of the cartridge holder 303 slightly varies according to products under the influence of manufacture and assembly, so that it requires fine adjustment in the final stage of the assembly. Actually, in order to adjust the range of vertical movement of the lifter, an adjust screw 312 is used in Japanese Patent Application Laid-Open No. 9-17137.
If the descent of the cartridge holder 303 is prevented by the springy member, as mentioned before, however, the prevention is easily canceled by vibration or shock, and fine adjustment operation by the adjust screw in the final stage of the assembly, if necessary, requires so much labor.
The object of the present invention is to provide a disk drive unit provided with a magnetic head lift mechanism of a simple construction, which is highly resistant to vibration and shock and sturdy.
In order to achieve the above object, a disk drive unit according to the present invention comprises a first arm and a second arm fitted with a first magnetic head and a second magnetic head, respectively, and capable of moving toward and away from each other, arm urging means urging the first and second arms to move toward each other, and a slide piece capable of moving toward the first and second arms from beside the first and second arms and engaging at least one of the arms, thereby maintaining the distance between the first and second arms. When the slide piece retreats to a position where it engages neither of the first nor second arms, the first and second arms are moved toward each other by the arm urging means.
In the disk drive unit according to the present invention, the slide piece slides toward the arms from beside the arms and engage the arms, thereby supporting the arms from below. Thus, the arms can be supported securely, and there is no possibility of the slide piece being disengaged from the arms if it is subjected to vibration or shock.